Anne Karin Kristoffersen

• Haugsten, Helene Rygvold; Kristoffersen, Anne Karin; Enersen, Morten; Thiede, Bernd; Søland, Tine Merete & Haug, Trude M. [Vis alle 7 forfattere av denne artikkelen] (2025). Bacterial extracellular vesicles from Porphyromonas gingivalis – proteomic profile and influence on oral fibroblasts. Archives of Oral Biology. ISSN 0003-9969. 181. doi: 10.1016/j.archoralbio.2025.106424. Fulltekst i vitenarkiv Vis sammendrag

  Objectives In this study, we aimed to explore the protein content of bacterial extracellular vesicles (bEVs) from three strains of Porphyromonas gingivalis, an anaerobic gram-negative bacterium closely associated with periodontitis. Additionally, we aimed to investigate the effects of bEV uptake on human oral fibroblasts, to better understand the role of these vesicles in the pathogenesis of periodontitis. Design Liquid chromatography-mass spectrometry was performed on bEVs from three strains of P. gingivalis with different virulence: ATCC 33277, A7A1–28, and W83. Three key proteins associated with virulence were validated using dot blot. Proliferation and viability of human oral fibroblasts after incubation with bEVs were assessed at different timepoints and different concentrations of bEVs. Results A total of 307 proteins were identified in the bEVs from the three strains of P. gingivalis. Among those were several relevant for virulence, for example gingipains, fimbriae, and peptidyl-arginine deiminase (PPAD). When oral fibroblasts were exposed to bEVs from A7A1–28 or W83, proliferation was significantly affected after 12 and 24 h at one bEV concentration. Furthermore, viability was significantly affected by bEVs from W83 at several timepoints and bEV concentrations. bEVs from ATCC 33277 did not induce any significant changes. Conclusion Several proteins associated with virulence were detected in bEVs from all three strains of P. gingivalis, with varying abundance. Uptake of these bEVs can influence human cells, as exemplified by changes in viability and proliferation.

• Haugsten, Helene Rygvold; Lipka, Aleksandra Katarzyna; Kristoffersen, Anne Karin; Enersen, Morten; Nieminen, Anni & Søland, Tine Merete [Vis alle 8 forfattere av denne artikkelen] (2025). Metabolic Changes in Oral Fibroblasts After Exposure to Bacterial Extracellular Vesicles From Three Strains of Porphyromonas gingivalis. Cellular Microbiology. ISSN 1462-5814. 2025(1). doi: 10.1155/cmi/7515004. Fulltekst i vitenarkiv Vis sammendrag

  Aims Porphyromonas gingivalis is a keystone pathogen in periodontitis that releases bacterial extracellular vesicles (bEVs) with a content derived from the membrane and cytosol of the bacteria itself. The bEVs are taken up by host tissue cells, such as oral fibroblasts, yet their effects on human cells remain incompletely understood. Methods The aim of this study was to investigate the impact of bEVs on human oral fibroblasts. Targeted liquid chromatography–mass spectrometry was used to assess changes in the metabolome of these cells following exposure to bEVs from three strains of P. gingivalis (ATCC 33277, A7A1-28, and W83). Metabolite content of the bEVs from each strain was also characterized. Result Metabolomic analyses revealed both common and strain-specific metabolites in the bEVs from these strains. Additionally, pathways mainly associated with amino acid metabolism were enriched for all. Following exposure to bEVs, the fibroblasts exhibited a metabolic shift in energy metabolism. In particular, fibroblasts incubated with bEVs from ATCC 33277 had a unique profile of enriched pathways after 10 min. However, after 24 h, this profile changed and became more similar to the profile in fibroblasts incubated with bEVs from the two more pathogenic strains. Pathway analysis revealed enrichment of glycerophospholipid and butanoate metabolism for fibroblasts exposed to all the bEVs. Additionally, altered sphingolipid metabolism was observed in fibroblasts following exposure to bEVs from ATCC 33277. Conclusion Our findings demonstrate that bEVs derived from P. gingivalis strains can induce changes in cellular processes in fibroblasts. This suggests a role of bEVs in the pathogenesis of periodontitis.

• Haugsten, Helene Rygvold; Kristoffersen, Anne Karin; Haug, Trude Marie; Søland, Tine Merete; Øvstebø, Reidun & Aass, Hans Christian [Vis alle 8 forfattere av denne artikkelen] (2023). Isolation, characterization, and fibroblast uptake of bacterial extracellular vesicles from Porphyromonas gingivalis strains. MicrobiologyOpen. 12(5). doi: 10.1002/mbo3.1388. Fulltekst i vitenarkiv Vis sammendrag

  Periodontitis is an inflammatory condition caused by bacteria and represents a serious health problem worldwide as the inflammation damages the supporting tissues of the teeth and may predispose to systemic diseases. Porphyromonas gingivalis is considered a keystone periodontal pathogen that releases bacterial extracellular vesicles (bEVs) containing virulence factors, such as gingipains, that may contribute to the pathogenesis of periodontitis. This study aimed to isolate and characterize bEVs from three strains of P. gingivalis, investigate putative bEV uptake into human oral fibroblasts, and determine the gingipain activity of the bEVs. bEVs from three bacterial strains, ATCC 33277, A7A1-28, and W83, were isolated through ultrafiltration and size-exclusion chromatography. Vesicle size distribution was measured by nano-tracking analysis (NTA). Transmission electron microscopy was used for bEV visualization. Flow cytometry was used to detect bEVs and gingipain activity was measured with an enzyme assay using a substrate specific for arg-gingipain. The uptake of bEVs into oral fibroblasts was visualized using confocal microscopy. NTA showed bEV concentrations from 108 to 1011 particles/mL and bEV diameters from 42 to 356 nm. TEM pictures demonstrated vesicle-like structures. bEV-gingipains were detected both by flow cytometry and enzyme assay. Fibroblasts incubated with bEVs labeled with fluorescent dye displayed intracellular localization consistent with bEV internalization. In conclusion, bEVs from P. gingivalis were successfully isolated and characterized, and their uptake into human oral fibroblasts was documented. The bEVs displayed active gingipains demonstrating their origin from P. gingivalis and the potential role of bEVs in periodontitis.

• Monsen, Ragnhild Elisabeth; Kristoffersen, Anne Karin; Gay, Caryl; Herlofson, Bente Brokstad; Fjeld, Katrine Gahre & Hove, Lene Hystad [Vis alle 10 forfattere av denne artikkelen] (2023). Identification and susceptibility testing of oral candidiasis in advanced cancer patients. BMC Oral Health. 23(1). doi: 10.1186/s12903-023-02950-y. Fulltekst i vitenarkiv Vis sammendrag

  Background Patients with advanced cancer are prone to develop different opportunistic oral infection due to anti-cancer treatment or the malignancies themselves. Studies of oral fungal samples show an increased prevalence of non-Candida albicans species in mixed oral infections with Candida albicans. Non-C. albicans and C. albicans are associated with varying degrees of resistance to azoles, which may have implications for treatment. This study aimed to assess the diversity and antifungal susceptibility of Candida species detected in the oral cavity. Methods An observational study with microbiological analysis was conducted. Clinical fungal isolates were collected from patients in a hospice unit in 2014–2016. Isolates were re-grown on chromID® Candida plates in 2020. Single colony of each species was re-cultivated and prepared for biochemical identification with a VITEK2® system and verified by gene sequencing. Etest was performed on RPMI agar, and the antifungals fluconazole, amphotericin B, anidulafungin and nystatin were applied. Results Fifty-six isolates from 45 patients were identified. Seven different Candida species and one Saccharomyces species were detected. The results of biochemical identification were confirmed with sequencing analysis. Thirty-six patients had mono infection, and nine out of 45 patients had 2–3 different species detected. Of C. albicans strains, 39 out of 40 were susceptible to fluconazole. Two non-C. albicans species were resistant to fluconazole, one to amphotericin B and three to anidulafungin. Conclusion C. albicans was the predominant species, with a high susceptibility to antifungal agents. Different Candida species occur in both mono and mixed infections. Identification and susceptibility testing may therefore lead to more effective treatment and may prevent the development of resistance among patients with advanced cancer. Trail registration The study Oral Health in Advanced Cancer was registered at ClinicalTrials.gov (#NCT02067572) in 20/02/2014.

• Gürsoy, Mervi; Rautava, Jaana; Pussinen, Pirkko; Kristoffersen, Anne Karin; Enersen, Morten & Loimaranta, Vuokko [Vis alle 7 forfattere av denne artikkelen] (2023). Salivary IgA and IgG Antibody Responses against Periodontitis-Associated Bacteria in Crohn’s Disease. International Journal of Molecular Sciences. ISSN 1661-6596. 24(3). doi: 10.3390/ijms24032385. Fulltekst i vitenarkiv Vis sammendrag

  Elevated serum immunoglobulin (Ig) antibody levels are observed in Crohn’s disease patients. The aim of this study was to evaluate the salivary IgA and IgG antibody levels against Porphyromonas gingivalis, Tannerella forsythia, Aggregatibacter actinomycetemcomitans, and Prevotella intermedia in Crohn’s disease patients. Eighty-eight participants (47 Crohn’s disease patients and 41 systemically healthy age- and gender-matched controls) were included in the study. Oral and medical health statuses were recorded and salivary samples were collected. Salivary P. gingivalis, T. forsythia, A. actinomycetemcomitans, and P. intermedia carriage were analyzed with DNA sequencing technique, salivary levels of IgG1, IgG2, IgG3, IgG4, and IgM were measured with the Luminex® xMAP™ technique, and salivary IgA and IgG antibody levels against P. gingivalis, T. forsythia, A. actinomycetemcomitans, and P. intermedia were detected by ELISA. As result, higher salivary IgG2 (p = 0.011) and IgG3 (p = 0.006), P. gingivalis IgA (p < 0.001), A. actinomycetemcomitans IgG (p = 0.001), and P. intermedia IgG (p < 0.001) antibody levels were detected in the Crohn’s disease group compared to the controls. Salivary P. gingivalis carriage was lower in the Crohn’s disease group in comparison to the controls (p = 0.024). In conclusion, salivary IgA antibody responses against P. gingivalis and IgG antibody responses against P. intermedia have independent associations with Crohn’s disease.

• Lawrence, Graeme; Midtervoll, Ingvild K.; Samuelsen, Sven Ove; Kristoffersen, Anne Karin; Enersen, Morten & Håheim, Lise Lund (2022). The blood microbiome and its association to cardiovascular disease mortality: case-cohort study. BMC Cardiovascular Disorders. 22(1). doi: 10.1186/s12872-022-02791-7. Fulltekst i vitenarkiv Vis sammendrag

  Background Little is known about the association between bacterial DNA in human blood and the risk of cardiovascular disease (CVD) mortality. Methods A case-cohort study was performed based on a 9 ½ year follow-up of the Oslo II study from 2000. Eligible for this analysis were men born in 1923 and from 1926 to 1932. The cases were men (n = 227) who had died from CVD, and the controls were randomly selected participants from the same cohort (n = 178). Analysis of the bacterial microbiome was performed on stored frozen blood samples for both cases and controls. Association analyses for CVD mortality were performed by Cox proportional hazard regression adapted to the case-cohort design. We used the Bonferroni correction due to the many bacterial genera that were identified. Results Bacterial DNA was identified in 372 (82%) of the blood samples and included 78 bacterial genera from six phyla. Three genera were significantly associated with CVD mortality. The genera Kocuria (adjusted hazard ratio (HR) 8.50, 95% confidence interval (CI) (4.05, 17.84)) and Enhydrobacter (HR 3.30 (2.01, 5.57)) indicate an association with CVD mortality with increasing levels. The genera Paracoccus (HR 0.29 (0.15, 0.57)) was inversely related. Significant predictors of CVD mortality were: the feeling of bad health; and the consumption of more than three cups of coffee per day. The following registered factors were borderline significant, namely: a history of heart failure; increased systolic blood pressure; and currently taking antihypertensive drugs now, versus previously. Conclusions The increasing levels of two bacterial genera Kocuria (skin and oral) and Enhydrobacter (skin) and low levels of Paracoccus (soil) were associated with CVD mortality independent of known risk factors for CVD.

• Rusthen, Shermin; Kristoffersen, Anne Karin; Young, Alix; Galtung, Hilde; Petrovski, Beata & Palm, Øyvind [Vis alle 8 forfattere av denne artikkelen] (2019). Dysbiotic salivary microbiota in dry mouth and primary Sjögren’s syndrome patients. PLOS ONE. 14(6), s. 1–15. doi: 10.1371/journal.pone.0218319. Fulltekst i vitenarkiv Vis sammendrag

  Objectives Primary Sjögren’s syndrome (pSS) is an autoimmune disease characterized by reduced lacrimal and salivary secretion. Sicca symptoms together with fatigue and musculoskeletal pain can significantly reduce the patients’ quality of life. Furthermore, low salivary secretion may disrupt the oral microbial homeostasis. The aim of this study was to compare the salivary microbiota from pSS patients with patients with sicca symptoms not fulfilling the classification criteria for pSS (non-SS), and with healthy controls without sicca complaints. Methods Pellets from centrifuged chewing-stimulated whole saliva from pSS patients (n = 15), non-SS sicca patients (n = 15) and healthy controls (n = 15) were prepared. DNA was extracted and analyzed by 16S rRNA gene sequencing. The acquired sequencing data were performed using the human oral microbiome database (HOMD). Results We detected 42, 45, and 34 bacterial genera in saliva samples from pSS patients, non-SS sicca patients, and healthy controls, respectively. The most abundant genera in all samples were Prevotella, Veillonella, Streptococcus, and Haemophilus. At species level Streptococcus intermedius, Prevotella intermedia, Fusobacterium nucleatum subsp. vincentii, Porphyromonas endodontalis, Prevotella nancensis, Tannerella spp., and Treponema spp. were detected in the samples from pSS and non-SS only, while Porphyromonas pasteri was mostly found among the healthy controls. Conclusion Our study indicated dysbiosis in the salivary microbiota from pSS and non-SS patients compared to healthy controls. Additionally, the results showed that the salivary microbiome in the pSS group differed significantly from the non-SS group.

• Zandi, Homan; Petronijevic, Nikola; Mdala, Ibrahimu; Kristoffersen, Anne Karin; Enersen, Morten & Rocas, Isabela N. [Vis alle 8 forfattere av denne artikkelen] (2019). Outcome of endodontic retreatment Using 2 root canal irrigants and influence of infection on healing as determined by a molecular method: A Randomized Clinical Trial. Journal of Endodontics. ISSN 0099-2399. 45(9), s. 1089–1098.e5. doi: 10.1016/j.joen.2019.05.021. Fulltekst i vitenarkiv
• Hardersen, Line Rørslett; Enersen, Morten; Kristoffersen, Anne Karin; Ørstavik, Dag & Sunde, Pia Titterud (2019). Maintenance of the aseptic working field during endodontic treatment. Acta Odontologica Scandinavica. ISSN 0001-6357. s. 1–6. doi: 10.1080/00016357.2019.1606935. Fulltekst i vitenarkiv Vis sammendrag

  ABSTRACT Objective: The aim of this clinical quality study was to determine whether the aseptic working field is maintained during the endodontic procedure. Materials and methods: Bacterial samples were collected from the rubber dam of 27 patients during endodontic treatment performed by postgraduate students at the Department of Endodontics, University of Oslo. A bacterial sample was first obtained immediately after disinfection of the working field (A), and the second sample was collected just before obturation or dressing with calcium hydroxide cement (B). Aerobic cultivation technique and PCR were used for detection of bacterial growth and species. Results: All samples were negative on culturing except in one case, which showed positive results with cultivation in both sample A and B. Specie detected with cultivation technique were Streptococcus mitis. With PCR technique, 6 samples in 5 patients (11%), showed positive results. Species detected with PCR technique were Bacteroidales spp. Propionibacterium spp., Bacteroidetes spp., Prevotella nigrescens, Haemophilus parainfluenzae, Neisseria elongata, Alloprevotella tannerae, Capnocytophaga granulosa, Cardiobacterium hominis, Fusobacterium nucleatum and Streptococcus mitis. Conclusion: The present study showed that an aseptic working field was maintained throughout the endodontic procedure in 81% (22/27) of the cases after disinfection of the rubber dam.

• Olsen-Bergem, Heming; Kristoffersen, Anne Karin; Bjørnland, Tore & Aas, Jørn Arne (2018). Is it possible to contaminate the temporomandibular joint by arthrocentesis? Oral Surgery. ISSN 1752-2471. 11(3), s. 183–188. doi: 10.1111/ors.12331. Fulltekst i vitenarkiv Vis sammendrag

  Introduction: Bacterial contamination of the temporomandibular joint (TMJ) by needle penetration of the skin has previously been discussed as a contributing factor in joint arthritis. The purpose of this study was to investigate the presence of bacterial deoxyribonucleic acid (DNA) in synovial fluid, and to detect any possible iatrogenic contamination during arthrocentesis of the TMJ in patients with juvenile idiopathic arthritis and rheumatoid arthritis. Method: Synovial fluid (SF) and skin swab samples (before and after disinfection) were collected from 54 TMJs in 30 patients with TMJ arthritis. Bacterial detection and classification was performed using 16S rRNA pyrosequencing. Results: Bacterial DNA was detected in 31 joints (57%) in 19 patients (63%). In six 12 joints (20%) in six patients specific bacterial species were detected in both skin samples and in the TMJ, indicating a possible contamination. 22 different bacterial species were detected in synovial fluid from these six patients. Conclusion: Bacterial DNA in TMJ SF with contamination was detected in 20% of the patients. Studies are needed to evaluate the consequences of potential contamination with bacterial DNA in SF with regard to arthrocentesis and treatment of TMJ arthritis.

• Zandi, Homan; Kristoffersen, Anne Karin; Ørstavik, Dag; Rocas, Isabela; Siqueira, Jose F. & Enersen, Morten (2018). Microbial Analysis of Endodontic Infections in Root-filled Teeth with Apical Periodontitis before and after Irrigation using Pyrosequencing. Journal of Endodontics. ISSN 0099-2399. 44(3), s. 372–378. doi: 10.1016/j.joen.2017.11.019. Fulltekst i vitenarkiv
• Valegård, Karin; Andralojc, P. John; Haslam, Richard P.; Pearce, F. Grant; Eriksen, Gunilla Kristina & Madgwick, Pippa J. [Vis alle 12 forfattere av denne artikkelen] (2018). Structural and functional analyses of Rubisco from arctic diatom species reveal unusual posttranslational modifications. Journal of Biological Chemistry. ISSN 0021-9258. 293(34), s. 13033–13043. doi: 10.1074/jbc.RA118.003518. Fulltekst i vitenarkiv Vis sammendrag

  The catalytic performance of the major CO₂-assimilating enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), restricts photosynthetic productivity. Natural diversity in the catalytic properties of Rubisco indicates possibilities for improvement. Oceanic phytoplankton contain some of the most efficient Rubisco enzymes, and diatoms in particular are responsible for a significant proportion of total marine primary production as well as being a major source of CO₂ sequestration in polar cold waters. Until now, the biochemical properties and three-dimensional structures of Rubisco from diatoms were unknown. Here, diatoms from arctic waters were collected, cultivated, and analyzed for their CO₂-fixing capability. We characterized the kinetic properties of five and determined the crystal structures of four Rubiscos selected for their high CO₂-fixing efficiency. The DNA sequences of the rbcL and rbcS genes of the selected diatoms were similar, reflecting their close phylogenetic relationship. The Vmax and Km for the oxygenase and carboxylase activities at 25 °C and the specificity factors (Sc/o) at 15, 25, and 35 °C were determined. The Sc/o values were high, approaching those of mono- and dicot plants, thus exhibiting good selectivity for CO₂ relative to O₂. Structurally, diatom Rubiscos belong to form I C/D, containing small subunits characterized by a short βA–βB loop and a C-terminal extension that forms a β-hairpin structure (βE–βF loop). Of note, the diatom Rubiscos featured a number of posttranslational modifications of the large subunit, including 4-hydroxyproline, β-hydroxyleucine, hydroxylated and nitrosylated cysteine, mono- and dihydroxylated lysine, and trimethylated lysine. Our studies suggest adaptation toward achieving efficient CO₂ fixation in arctic diatom Rubiscos.

• Larsen, Olav Inge; Enersen, Morten; Kristoffersen, Anne Karin; Wennerberg, Ann; Bunæs, Dagmar Fosså & Lie, Stein Atle [Vis alle 7 forfattere av denne artikkelen] (2017). Antimicrobial effects of three different treatment modalities on dental implant surfaces. Journal of Oral Implantology. ISSN 0160-6972. 43(6), s. 429–436. doi: 10.1563/aaid-joi-D-16-00147. Fulltekst i vitenarkiv
• Hallmer, Fredrik; Bjørnland, Tore; Anderson, Gunilla; Becktor, Jonas P; Kristoffersen, Anne Karin & Enersen, Morten (2017). Bacterial diversity in medication-related osteonecrosis of the jaws. Oral surgery, oral medicine, oral pathology and oral radiology. ISSN 2212-4403. 123(4), s. 436–444. doi: 10.1016/j.oooo.2016.11.011. Fulltekst i vitenarkiv
• Rodrigues, Renata Costa Val; Zandi, Homan; Kristoffersen, Anne Karin; Enersen, Morten; Mdala, Ibrahimu & Ørstavik, Dag [Vis alle 8 forfattere av denne artikkelen] (2017). Influence of the apical preparation size and the irrigant type on bacterial reduction in root canal - treated teeth with apical periodontitis. Journal of Endodontics. ISSN 0099-2399. 43(7), s. 1058–1063. doi: 10.1016/j.joen.2017.02.004. Fulltekst i vitenarkiv
• Olsen-Bergem, Heming; Kristoffersen, Anne Karin; Bjørnland, Tore; Reseland, Janne Elin & Aas, Jørn Arne (2016). Juvenile idiopathic arthritis and rheumatoid arthritis: Bacterial diversity in temporomandibular joint synovial fluid in comparison with immunological and clinical findings. International Journal of Oral & Maxillofacial Surgery. ISSN 0901-5027. 45(3), s. 318–322. doi: 10.1016/j.ijom.2015.08.986. Fulltekst i vitenarkiv
• Langbach, Odd; Kristoffersen, Anne Karin; Abesha-Belay, Emnet; Enersen, Morten; Røkke, Ola & Olsen, Ingar (2016). Oral, intestinal, and skin bacteria in ventral hernia mesh implants. Journal of Oral Microbiology. 8:31854(1), s. 1–15. doi: 10.3402/jom.v8.31854. Fulltekst i vitenarkiv Vis sammendrag

  Background: In ventral hernia surgery, mesh implants are used to reduce recurrence. Infection after mesh implantation can be a problem and rates around 6–10% have been reported. Bacterial colonization of mesh implants in patients without clinical signs of infection has not been thoroughly investigated. Molecular techniques have proven effective in demonstrating bacterial diversity in various environments and are able to identify bacteria on a gene-specific level. Objective: The purpose of this study was to detect bacterial biofilm in mesh implants, analyze its bacterial diversity, and look for possible resemblance with bacterial biofilm from the periodontal pocket. Methods: Thirty patients referred to our hospital for recurrence after former ventral hernia mesh repair, were examined for periodontitis in advance of new surgical hernia repair. Oral examination included periapical radiographs, periodontal probing, and subgingival plaque collection. A piece of mesh (1×1 cm) from the abdominal wall was harvested during the new surgical hernia repair and analyzed for bacteria by PCR and 16S rRNA gene sequencing. From patients with positive PCR mesh samples, subgingival plaque samples were analyzed with the same techniques. Results: A great variety of taxa were detected in 20 (66.7%) mesh samples, including typical oral commensals and periodontopathogens, enterics, and skin bacteria. Mesh and periodontal bacteria were further analyzed for similarity in 16S rRNA gene sequences. In 17 sequences, the level of resemblance between mesh and subgingival bacterial colonization was 98–100% suggesting, but not proving, a transfer of oral bacteria to the mesh. Conclusion: The results show great bacterial diversity on mesh implants from the anterior abdominal wall including oral commensals and periodontopathogens. Mesh can be reached by bacteria in several ways including hematogenous spread from an oral site. However, other sites such as gut and skin may also serve as sources for the mesh biofilm.

• Andersen, Kari-Mette; Kristoffersen, Anne Karin; Ingebretsen, André; Vikholt, Katharina Johnsen; Ørtengren, Ulf Thore & Olsen, Ingar [Vis alle 8 forfattere av denne artikkelen] (2016). Diversity and anti-fungal susceptibility of Norwegian Candida glabrata clinical isolates. Journal of Oral Microbiology. 8(1). doi: 10.3402/jom.v8.29849. Fulltekst i vitenarkiv Vis sammendrag

  BACKGROUND: Increasing numbers of immunocompromised patients have resulted in greater incidence of invasive fungal infections with high mortality. Candida albicans infections dominate, but during the last decade, Candida glabrata has become the second highest cause of candidemia in the United States and Northern Europe. Reliable and early diagnosis, together with appropriate choice of antifungal treatment, is needed to combat these challenging infections. OBJECTIVES: To confirm the identity of 183 Candida glabrata isolates from different human body sites using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and VITEK®2, and to analyze isolate protein profiles and antifungal susceptibility. The minimum inhibitory concentration (MIC) of seven antifungal drugs was determined for the isolates to elucidate susceptibility. DESIGN: A total of 183 C. glabrata isolates obtained between 2002 and 2012 from Norwegian health-care units were analyzed. For species verification and differentiation, biochemical characterization (VITEK®2) and mass spectrometry (MALDI–TOF) were used. MIC determination for seven antifungal drugs was undertaken using E-tests®. RESULTS: Using VITEK®2, 92.9% of isolates were identified as C. glabrata, while all isolates (100%) were identified as C. glabrata using MALDI-TOF. Variation in protein spectra occurred for all identified C. glabrata isolates. The majority of isolates had low MICs to amphotericin B (≤1 mg/L for 99.5%) and anidulafungin (≤0.06 mg/L for 98.9%). For fluconazole, 18% of isolates had MICs >32 mg/L and 82% had MICs in the range ≥0.016 mg/L to ≤32 mg/L. CONCLUSIONS: Protein profiles and antifungal susceptibility characteristics of the C. glabrata isolates were diverse. Clustering of protein profiles indicated that many azole resistant isolates were closely related. In most cases, isolates had highest susceptibility to amphotericin B and anidulafungin. The results confirmed previous observations of high MICs to fluconazole and flucytosine. MALDI-TOF was more definitive than VITEK®2 for C. glabrata identification.

• Zandi, Homan; Rodrigues, Renata C.V.; Kristoffersen, Anne Karin; Enersen, Morten; Mdala, Ibrahimu & Ørstavik, Dag [Vis alle 8 forfattere av denne artikkelen] (2016). Antibacterial Effectiveness of 2 Root Canal Irrigants in Root-filled Teeth with Infection: A Randomized Clinical Trial. Journal of Endodontics. ISSN 0099-2399. 42(9), s. 1307–1313. doi: 10.1016/j.joen.2016.06.006. Fulltekst i vitenarkiv
• Armingohar, Zahra; Jørgensen, Jørgen J.; Kristoffersen, Anne Karin; Schenck, Karl & Dembic, Zlatko (2015). Polymorphisms in the interleukin-10 gene and chronic periodontitis in patients with atherosclerotic and aortic aneurysmal vascular diseases. Journal of Oral Microbiology. 7(1), s. 1–8. doi: 10.3402/jom.v7.26051. Fulltekst i vitenarkiv Vis sammendrag

  Background: Chronic periodontitis (CP), atherosclerotic and aortic aneurysmal vascular diseases (VD) are chronic inflammatory conditions with multifactorial etiologies, including involvement of predisposing genetic factors. In a previous study, polymorphisms in the gene for the anti-inflammatory interleukin-1 receptor antagonist were associated with CP in patients with VD. Objective: This study investigates whether polymorphisms in the gene for the anti-inflammatory interleukin-10 (IL10) could be related to CP in the same manner. Methods: Seventy-two patients with VD of whom 35 had CP were genotyped for single nucleotide polymorphisms (SNPs) in the IL10 −592 (rs1800872), −819 (rs1800871), and −1,082 (rs1800896) gene by Taqman rtPCR method and by DNA sequencing. Results: The C alleles and C/C genotypes of IL10 −592 and IL10 −819 frequencies were significantly higher, while the frequencies of the IL10 −592 (C/A) and IL10 −819 (C/T) heterozygote genotypes were significantly lower in the VD group with CP compared to those without CP. The IL10 haplotype ATA frequency (−1,082, −819, −592) showed a trend to a significant difference between the two groups indicating protection against CP. Conclusions: Taken together, our findings suggest an independent association of genetic polymorphisms in the IL-10 gene locus with CP in patients with VD. Development of CP and the implications on vascular disease emphasize the importance of early detection and adequate treatment of periodontitis among these patients.

• Armingohar, Zahra; Jørgensen, Jørgen J.; Kristoffersen, Anne Karin; Abesha-Belay, Emnet & Olsen, Ingar (2014). Bacteria and bacterial DNA in atherosclerotic plaque and aneurysmal wall biopsies from patients with and without periodontitis. Journal of Oral Microbiology. 6, s. 1–13. doi: 10.3402/jom.v6.23408. Fulltekst i vitenarkiv Vis sammendrag

  Background: Several studies have reported an association between chronic periodontitis (CP) and cardiovascular diseases. Detection of periodontopathogens, including red complex bacteria (RCB), in vascular lesions has suggested these bacteria to be involved in the pathogenesis of atherosclerosis and abdominal aortic aneurysms. Objective: In this study, we investigate bacteria and their DNA in vascular biopsies from patients with vascular diseases (VD; i.e. abdominal aortic aneurysms, atherosclerotic carotid, and common femoral arteries), with and without CP. Methods: DNA was extracted from vascular biopsies selected from 40 VD patients: 30 with CP and 10 without CP. The V3-V5 region of the 16S rDNA (V3-V5) was polymerase chain reaction (PCR)-amplified, and the amplicons were cloned into Escherichia coli, sequenced, and classified (GenBank and the Human Oral Microbiome database). Species-specific primers were used for the detection of Porphyromonas gingivalis. In addition, 10 randomly selected vascular biopsies from the CP group were subjected to scanning electron microscopy (SEM) for visualization of bacteria. Checkerboard DNA–DNA hybridization was performed to assess the presence of RCB in 10 randomly selected subgingival plaque samples from CP patients. Results: A higher load and mean diversity of bacteria were detected in vascular biopsies from VD patients with CP compared to those without CP. Enterobacteriaceae were frequently detected in vascular biopsies together with cultivable, commensal oral, and not-yet-cultured bacterial species. While 70% of the subgingival plaque samples from CP patients showed presence of RCB, only P. gingivalis was detected in one vascular biopsy. Bacterial cells were seen in all 10 vascular biopsies examined by SEM. Conclusions: A higher bacterial load and more diverse colonization were detected in VD lesions of CP patients as compared to patients without CP. This indicated that a multitude of bacterial species both from the gut and the oral cavity, rather than exclusively periodontopathogens, may be involved as additional risk factors in the pathogenesis of VD.

• Armingohar, Zahra; Jørgensen, Jørgen J.; Kristoffersen, Anne Karin; Schenck, Karl & Dembic, Zlatko (2014). Polymorphisms in the interleukin-1 gene locus and chronic periodontitis in patients with atherosclerotic and aortic aneurysmal vascular diseases. Scandinavian Journal of Immunology. ISSN 0300-9475. 79(5), s. 338–345. doi: 10.1111/sji.12166. Fulltekst i vitenarkiv Vis sammendrag

  Chronic periodontitis (CP) and atherosclerotic and aortic aneurysmal vascular diseases (VD) are inflammatory conditions that share a number of predisposing factors. They have a complex genetic heritability and may share genetic risk factors, but a well-defined relationship is still not determined. In addition, distinct genetic patterns of predisposition have been associated with these diseases. Here, we investigated the association of polymorphisms in the IL-1 gene locus with CP in a case-case study analysing VD patients with or without CP. Seventy-four patients with VD of whom 36 had CP were genotyped for single nucleotide polymorphisms in the IL1A -889 (rs1800587), IL1B +3954 (rs1143634) and IL1B at -511 (rs16944) genes and for VNTR polymorphisms in the IL1RN gene. A significantly higher frequency (17%) for allele 1 (four repeats) of the IL1RN VNTR gene was found among the VD patients with CP compared to those without CP. In addition, the frequency of the IL1RN VNTR genotypes 1/1 (4/4 repeats) and 2/2 (2/2 repeats) were significantly higher and lower, respectively, in VD patients with CP. These findings suggest an association of genetic polymorphisms in the IL1-gene locus with risk for CP in patients with VD. The carriage of the risk genotypes, the development and the subsequent influence of CP on systemic health may constitute an additional burden in the pathogenesis of VD. This emphasizes the importance of effective periodontal treatment in patients with VD.

• Kristoffersen, Anne Karin; Enersen, Morten; Kverndokk, Ellen Kristine; Sunde, Pia Titterud; Landin, Maria Augusta Dos S Silva & Solheim, Tore [Vis alle 8 forfattere av denne artikkelen] (2012). Human papillomavirus subtypes in oral lesions compared to healthy oral mucosa. Journal of Clinical Virology. ISSN 1386-6532. 53(4), s. 364–366. doi: 10.1016/j.jcv.2011.12.023. Fulltekst i vitenarkiv
• Kristoffersen, Anne Karin (2011). Laboratory methods for analyzing correlation between periodontitis and cardiovascular disease. I Håheim, Anne-Lise Lund (Red.), Oral infections and cardiovascular disease. Bentham Science Publishers Ltd. ISSN 9781608052325. s. 65–77. Fulltekst i vitenarkiv
• Leuckfeld, Inga; Paster, Bruce J; Kristoffersen, Anne Karin & Olsen, Ingar (2010). Diversity of Veillonella spp. from subgingival plaque by polyphasic approach. APMIS - Journal of Pathologiy, Microbiology and Immunology. ISSN 0903-4641. 118(3), s. 230–242. doi: 10.1111/j.1600-0463.2009.02584.x. Fulltekst i vitenarkiv

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• Monsen, Ragnhild Elisabeth; Kristoffersen, Anne Karin; Gay, Caryl; Herlofson, Bente Brokstad; Fjeld, Katrine Gahre & Hove, Lene Hystad [Vis alle 10 forfattere av denne artikkelen] (2022). Orale soppinfeksjoner - mer enn Candida albicans: mikrobiologiske analyser av prøver fra alvorlig syke pasienter med kreft. Fulltekst i vitenarkiv Vis sammendrag

  Bakgrunn Pasienter med alvorlig kreftsykdom er utsatte for orale soppinfeksjoner, grunnet sykdommen, kreftbehandling og/eller svekket immunforsvar. Orale soppinfeksjon påvirker pasienters matlyst, ernæringstilstand og livskvalitet. Candida albicans er en vanlig soppart i munnhulen, men forekomst av non-albicans Candida-arter, og i kombinasjon med C. albicans, er økende. Artene har varierende toleranse for antimykotiske midler, det kan gi behandlingsutfordringer. Hensikten med studien var å identifisere og resistensteste Candida sopparter i munnhulen til alvorlig syke pasienter med kreft. Metode Sopprøver tatt under studien Oral Health in Advanced Cancer i perioden 2014 – 2016, ble analysert høsten 2020. Pasientprøvene ble re-dyrket ved Institutt for oral biologi, Universitetet i Oslo. Soppartene ble identifisert biokjemisk og ved DNA sekvensering, og resistenstestet for antimykotiske legemidler: fluconazole, amphotericin B, anidulafungin og nystatin. Resultat Vi analyserte totalt 56 isolater fra 45 pasienter og identifiserte syv Candida arter og en Saccharomyces. Til sammen hadde 36 pasienter oppvekst av én soppart, og 9 pasienter hadde 2 til 3 ulike sopparter i munnhulen. Av C. albicans artene var 39 av 40 følsomme for fluconazole. To Candida parapsilosis og en Candida tropicalis var resistent mot anidulafungin. En C. tropicalis var resistent mot anidulafungin. En Candida glabrata var resistent mot fluconazole. Konklusjon Studien viste at forskjellige Candida arter forekommer både i monoinfeksjoner og blandingsinfeksjoner. C. albicans var dominerende med høy følsomhet for antimykotiske midler. Blandingsinfeksjoner kan komplisere behandlingen og forårsake gjentagende infeksjoner. Mikrobiologiske prøver og analyser med identifisering og resistenstesting, bør være en del av utredningen hos pasienter med alvorlig og tilbakevendende orale soppinfeksjoner.

• Monsen, Ragnhild Elisabeth; Kristoffersen, Anne Karin; Gay, Caryl; Herlofson, Bente Brokstad; Fjeld, Katrine Gahre & Hove, Lene Hystad [Vis alle 10 forfattere av denne artikkelen] (2022). Identification and susceptibility testing of oral candidiasis in advanced cancer patients – an important diagnostic tool. Fulltekst i vitenarkiv Vis sammendrag

  Background: Candida albicans is the most common fungal species detected in the oral cavity. Studies of oral fungal samples have shown an increased prevalence of non-C. albicans species in mixed infection with C. albicans. Non-C. albicans and C. albicans are associated with varying degrees of resistance to azole. This may have implications for treatment, due to acquired antifungal resistance. Aims: To assess the diversity and susceptibility of detected Candida species in the oral cavity in patients with advanced cancer. Methods: Clinical fungal isolates sampled in 2014-2016 from 45 patients in a hospice unit were analyzed. A total of 56 isolates were grown on chromID Candida plates. After phenotypic identification by colour of the colonies, one single colony of each species was re-cultivated and prepared for identification on a VITEK2® system. Susceptibility testing with E-test was performed on RPMI agar, and the antifungal agents fluconazole, amphotericin B, anidulafungin and nystatin were tested. Results: A total of 56 Candida isolates were identified. The diversity of Candida species was dominated by C. albicans at 89%, followed by C. glabrata 11%, C. parapsilosis 7%, C. tropicalis 4%, C. krusei 2%, C. guilliermondii 2% and C. dubliniesis 2%. Thirty-six patients had monoculture, and nine patients had 2-3 different species detected. Almost all C. albicans strains (97.5%) were susceptible to fluconazole. One C. parapsilosis and one C. tropicalis strain were resistant to anidulafungin. One C. glabrata was resistant to fluconazole and another was just below the threshold for resistance. Conclusion: C. albicans was the most prevalent Candida species in our sample. Variation in susceptibility was observed in patients with both C. albicans and C. glabrata. Combinations of Candida species and the lack of identification and susceptibility testing may lead to inadequate treatment and accelerate the development of resistance.

• Monsen, Ragnhild Elisabeth; Kristoffersen, Anne Karin; Gay, Caryl; Herlofson, Bente Brokstad; Fjeld, Katrine Gahre & Hove, Lene Hystad [Vis alle 10 forfattere av denne artikkelen] (2022). Oral candidiasis in advanced cancer – identification and susceptibility testing of detected Candida species. Fulltekst i vitenarkiv Vis sammendrag

  Introduction: Candida albicans is the most common fungal species in the oral cavity. Increased prevalence of non-C. albicans are detected, and co-infection with C. albicans may have implications for treatment, due to antifungal resistance. The aim of the study was to assess the diversity and susceptibility of oral yeasts in patients with advanced cancer. Methods: Clinical fungal isolates were sampled in 2014-2016 from 45 patients in a hospice unit. Totally 56 isolates were grown on chromID Candida plates, prepared for biochemical identification, and controlled with DNA sequencing. E-test was performed with the antifungal agents fluconazole, amphotericin B, anidulafungin and nystatin were tested. Results: A total of 56 isolates were identified. Candida species was dominated by C. albicans at 71%, followed by C. glabrata 9%, C. parapsilosis 5%, C. tropicalis 4%, C. krusei 2%, C. guilliermondii 2% and C. dubliniesis 2%. Nine patients had 2-3 different species. C. albicans strains were susceptible to fluconazole in 97.5%. One C. parapsilosis and one C. tropicalis strain were resistant to anidulafungin. One C. glabrata was resistant to fluconazole and another was just below the threshold for resistance. The sequencing confirmed the biochemical identification. Conclusion: C. albicans was the most prevalent species. Variation in susceptibility was observed in patients with mixed colonies. Combinations of Candida species and the lack of identification and susceptibility testing may lead to inadequate treatment.

• Rogala, Agnieszka; Kristoffersen, Anne Karin; Enersen, Morten; Sapkota, Dipak & Küntziger, Thomas M. (2021). Defining the role of Porphyromonas gingivalis’ peptidyl arginine deiminase (PPAD) in oral carcinoma. Fulltekst i vitenarkiv
• Rogala, Agnieszka; Follin-Arbelet, Benoit; Kristoffersen, Anne Karin; Enersen, Morten; Sapkota, Dipak & Küntziger, Thomas M. (2019). Defining the role of Porphyromonas gingivalis peptidyl arginine deiminase (PPAD) in oral carcinoma. Fulltekst i vitenarkiv
• Rusthen, Shermin; Kristoffersen, Anne Karin; Young, Alix; Galtung, Hilde; Enersen, Morten & Jensen, Janicke Liaaen (2018). The Salivary Microbiota Profile in Reduced and Normal Salivation. Fulltekst i vitenarkiv
• Langbach, Odd; Kristoffersen, Anne Karin; Abesha-Belay, Emnet; Enersen, Morten & Olsen, Ingar (2016). Nett i bukveggen hos brokkopererte inneholder orale mikrober. Den norske tannlegeforenings Tidende. ISSN 0029-2303. 126(8), s. 610–611. Fulltekst i vitenarkiv
• Hallmer, Fredrik; Bjørnland, Tore; Kristoffersen, Anne Karin; Anderson, Gunilla & Enersen, Morten (2015). THE ASSOCIATION BETWEEN ORAL MICROFLORA AND BISPHOSPHONATE OR DENOSUMAB INDUCED OSTEONECROSIS - abstract ICOMS 2015 - International Conference on Oral and Maxillofacial Surgery, Melbourne October 2015. ICOMS 2015 - International Conference on Oral and Maxillofacial Surgery. Fulltekst i vitenarkiv
• Hallmer, Fredrik; Bjørnland, Tore; Kristoffersen, Anne Karin; Anderson, Gunilla & Enersen, Morten (2015). The association between oral microflora and bisphosphonate or denosumab induced osteonecrosis. International Journal of Oral & Maxillofacial Surgery. ISSN 0901-5027. 44, s. e76–e76. doi: 10.1016/j.ijom.2015.08.587. Fulltekst i vitenarkiv
• Midtervoll, Ingvild K.; Enersen, Morten; Kristoffersen, Anne Karin; Samuelsen, Sven Ove & Håheim, Lise Lund (2014). Detection of Periodontal Pathogens in Blood from Patients With Cardiovascular Disease. Oral Presentation. Fulltekst i vitenarkiv
• Zandi, Homan; Rodrigues, Renata C. V.; Kristoffersen, Anne Karin; Ørstavik, Dag; Siqueira, Jose F. & Rocas, Isabela [Vis alle 7 forfattere av denne artikkelen] (2014). Clinical effectiveness of two antimicrobial irrigants in endodontically treated teeth. Poster presentation. Fulltekst i vitenarkiv
• Andersen, Kari-Mette; Enersen, Morten; Kristoffersen, Anne Karin; Ingebretsen, André; Ørtengren, Ulf Thore & Gaustad, Peter [Vis alle 7 forfattere av denne artikkelen] (2014). Phenotypic characterization of Candida glabrata from blood, respiratory and gastrointestinal tracts. Fulltekst i vitenarkiv
• Andersen, Kari-Mette; Enersen, Morten; Kristoffersen, Anne Karin; Ingebretsen, André; Ørtengren, Ulf Thore & Gaustad, Peter [Vis alle 7 forfattere av denne artikkelen] (2014). Phenotypic Characterization of Candida glabrata from Blood, Respiratory and Gastrointestinal Tracts. Fulltekst i vitenarkiv
• Andersen, Kari-Mette; Enersen, Morten; Kristoffersen, Anne Karin; Ingebretsen, André; Ørtengren, Ulf Thore & Gaustad, Peter [Vis alle 7 forfattere av denne artikkelen] (2014). Phenotypic Characterization of Candida glabrata from Blood, Respiratory and Gastrointestinal Tracts. Poster presentation. Fulltekst i vitenarkiv
• Midtervoll, Ingvild K.; Enersen, Morten; Kristoffersen, Anne Karin; Samuelsen, Sven Ove; Olsen, Ingar & Håheim, L.L. (2014). Detection of Periodontal Pathogens in Blood from Patients with Cardiovascular Disease. Poster presentation. Fulltekst i vitenarkiv
• Andersen, Kari-Mette; Enersen, Morten; Kristoffersen, Anne Karin; Ingebretsen, André; Ørtengren, Ulf Thore & Gaustad, Peter [Vis alle 7 forfattere av denne artikkelen] (2014). Phenotypic Characterization of Candida glabrata from Blood, Respiratory and Gastrointestinal Tracts. Oral Presentation. Fulltekst i vitenarkiv
• Andersen, Kari-Mette; Enersen, Morten; Kristoffersen, Anne Karin; Ingebretsen, André; Ørtengren, Ulf Thore & Gaustad, Peter [Vis alle 7 forfattere av denne artikkelen] (2014). Phenotypic diversity among clinical Candida glabrata strains in Norwegian health care unit. Oral presentation. Fulltekst i vitenarkiv
• Zandi, Homan; Rodrigues, Renata C. V.; Kristoffersen, Anne Karin; Ørstavik, Dag; Siqueira, Jose F. & Rocas, Isabela [Vis alle 7 forfattere av denne artikkelen] (2014). Clinical effectiveness of two antimicrobial irrigants in endodontically treated teeth. Oral presentation. Fulltekst i vitenarkiv Vis sammendrag

  Clinical Effectiveness of Two Antimicrobial Irrigants in Endodontically Treated Teeth Homan Zandi, DDS, Renata C. V. Rodrigues, DDS, Anne-Karin Kristoffersen, PhD, Dag Ørstavik, DDS, PhD, José F. Siqueira Jr, DDS, PhD, Isabela Rôças, DDS, PhD, Morten Enersen, DDS, PhD Abstract Background: Endodontic treatment of root-filled teeth with post-treatment disease is especially challenging. The outcome of endodontic treatment is significantly influenced by the presence of bacteria in the root canals at the time of filling. Sodium hypochlorite (NaOCl) is widely used as a root canal irrigant in different concentrations because of its pronounced antimicrobial activity and the ability of dissolving necrotic tissue and organic matter. Chlorhexidine gluconate (CHX) is an effective substitute for NaOCl due to its broad-spectrum antimicrobial efficacy against bacteria and its high dentin substantivity. It is less toxic against vital tissues than NaOCl but lacks tissue dissolving property. No culture-independent molecular study has compared the antimicrobial effectiveness of 1% NaOCl and 2% CHX in root-filled teeth with apical periodontitis (AP). Objectives: The aim of the present study was to compare the antibacterial properties of 1% NaOCl and 2% CHX in endodontically treated teeth with AP. Methods: Sixty-eight root-filled teeth with AP were randomly distributed in two irrigant groups. Bacterial samples were taken at baseline (S1), after chemomechanical preparation using either 1% NaOCl or 2% CHX as irrigant (S2), and after intracanal medication with calcium hydroxide at the second visit (S3). The bacterial samples were analyzed by 16S rRNA gene-based quantitative polymerase chain reaction (qPCR) for total bacteria, Enterococcus faecalis and Streptococcus spp.. Results: Preliminary results indicated bacterial DNA in all the samples at S1. E. faecalis was seldom found, but streptococci were frequent. The amount of bacterial DNA significantly declined following treatment in both groups (S2 and S3) (p<0.001). There was no significant difference between NaOCl and CHX groups in reducing total bacterial and streptococcal counts (p>0.05). Conclusion: Findings indicate that endodontic retreatment was equally effective in reducing the amount of bacteria in both irrigation groups. Keywords: Endodontics. Root canal irrigants.

• Midtervoll, Ingvild K.; Kristoffersen, Anne Karin; Enersen, Morten; Samuelsen, Sven Ove & Håheim, Lise Lund (2013). PERIODONTAL PATHOGENS – A POSSIBLE ROLE IN CARDIOVASCULAR DISEASE? Fulltekst i vitenarkiv Vis sammendrag

  Objective: The aim of this ongoing study is to investigate a possible role for periodontal pathogens in relation to cardiovascular disease (CVD) through detection of bacterial DNA in bloodsamples from participants of the Oslo II study. Materials and methods: The study design is a blinded case-cohort design where the cohort is men from Oslo, born between 1926 and 1932. The test group consists of 225 individuals who have died from CVD (myocardial infarction, aortic aneurysms or stroke), and the control group are 225 healthy men randomly picked from the cohort. After DNA extraction from blood samples in both groups, PCR amplification of the 16S rRNA bacterial gene will be performed, and PCR products of 650bp fragment will be verified on a 1,5% agarose gel. Bacterial species will be detected by high throughput sequencing of the PCR products, and results from test and control group will be correlated. Furthermore, results from three diagnoses in the test group will also be correlated separately to the controls. Correction for known risk factors such as smoking, physical inactivity, high blood pressure, total serum cholesterol and diabetes will be performed. Results: Preliminary results from PCR amplification of 260 blinded bloodsamples indicate bacterial DNA detection with the expected fragment size in 124 (48%) of the samples investigated so far.

• Solli, Silje Jeanette; Nguyen, Toan Duy; Kristoffersen, Anne Karin & Enersen, Morten (2014). RgpB-genet; en viktig virulensfaktor hos den periopatogene bakteriearten Porphyromonas gingivalis Et molekylærbiologisk studium. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  A study based on various strains of Porphyromonas gingivalis to identify genetic variation of the protease rgpB.

• Vikholt, Katharina Johnsen; Andersen, Kari-Mette; Kristoffersen, Anne Karin & Enersen, Morten (2014). Oral candidiasisand molecular epidemiology in Candida glabrata. Universitetet i Oslo. Fulltekst i vitenarkiv

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